China has officially ended its controversial one-child policy, with married couples now allowed to have two children.

The change, which was prompted by concerns over the country's ageing population and shrinking workforce, was announced in October by the ruling Communist Party and takes effect from the first day of 2016.

The policy was instituted in the late 1970s, and restricted couples to only a single offspring through a system of fines and even forced abortions.

For years the authorities argued it was a key contributor to China's economic boom and had prevented 400 million births.